bug#16745: Can't send SIGTSTP from Emacs through GDB

[Andreas Schwab]

Barry OReilly <gundaetiapo@gmail.com> writes:

> When running GDB in Emacs and sending SIGTSTP via C-c C-z to another
> Emacs ran under GDB, the Emacs under GDB does not appear to receive
> the SIGTSTP.
>
> Recipe:
>
>   ./src/emacs -Q
>   M-x gdb
>   gdb -i=mi src/emacs
>   run -Q
>   C-c C-z
>   [The Emacs under GDB is not stopped.]

Here the signal is sent to terminal process group associated with the
gdb command buffer, which includes the gdb process, but not the inferior
(which runs in its own pty).

> However, when I run GDB from the shell rather than from Emacs:
>
>   gdb src/emacs
>   run -Q
>   C-z
>   [The Emacs under GDB stopped.]

Here the terminal sends the signal to the foreground process group,
which includes the inferior (and not gdb).

This problem does not appear with the traditional gdb interface, since
it closely resembles the shell setup.  I recommend using gud-gdb
instead.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
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